3M Steri-Vac GS Series - Overview of GS Series Ethylene Oxide (EO) Sterilization Cycle; Cycle Stages and Descriptions

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3M
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Steri-Vac
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Sterilizer /Aerator GSSeries – Operator’sManual
12.3. Overview of GS Series Ethylene Oxide (EO) SterilizationCycle
12.3.1. Cycle Stages andDescriptions
3M™Steri-Vac™ Sterilizer/Aerator GS Series ethylene oxide (EO) sterilization cycles consist of ten stages. After the sterilization cycle is complete, an aeration cycle is required to remove any
residual EO from the medical devices per the manufacturers’ instructions for use(IFUs).
While a sterilization cycle is running, icons on the bottom of the display screen indicate the current stage of the cycle (both with a white box around them and in the stage indicator). Each icon,
and the corresponding sterilization cycle stage, is describedbelow.
Stage 1:Preheat Stage 6: EOExposure
The temperature of the sterilizer chamber is controlled to attain the pre-set operating temperature.
The time required to obtain the pre-set operating temperature will vary slightly from cycle to cycle,
up to 40minutes.
EO Exposure is the pre-set time period between the end of EO Injection and the beginning of EO
Removal when EO is sterilizing theload.
Stage 2: AirRemoval Stage 7: EORemoval
A vacuum is created to remove air from the chamber and load. The vacuum rate is dependent upon
the nature of the sterilization load, environmental conditions and preprogrammed vacuumrate.
During this stage, EO is removed from the sterilizer chamber but not necessarily removed from the
sterilizationload.
Stage 3: ChamberTest Stage 8:Flushing
The Chamber Test measures the integrity of the sealed system and chamber. The test is carried out
prior to the start of both the EO Injection stage and Conditioning stage at a pre-set vacuum level.
Once the vacuum level is obtained a 2minute equilibration time allows for pressure stabilization,
afterwards the pressure rise in the chamber is monitored for six (6) minutes. During this period, the
final chamber pressure measurement minus the initial chamber pressure measurement must be
less than 18mBar (1.8kPa).
During the Flushing stage of the sterilization cycle, the EO is removed from the load and the open
chamber space of the sterilization chamber. The chamber is repeatedly filled with filtered air and
cleared by avacuum.
The end of the Flushing stage contains 90minutes of locked aeration. During this aeration period
the chamber remains locked to all personnel (Operators, Supervisors, and Service). This aeration
time will be included in the cycle report as part of the total aeration timeelapsed.
In addition, the vent hood (i.e. exhaust hood) is monitored for appropriate air flow in standard cubic
feet per minute (SCFM). If the GS Series sterilizer detects the air flow in the vent hood is too low
(< 125SFCM) or if the vent hood option is disabled in the Site Setup Menu, the sterilizer door will
remain locked in Flushing stage until a minimum of three hours of aeration is fulfilled during the
Flushing stage. This aeration time will be included in the cycle report as part of the total aeration
timeelapsed.
Stage 4:Conditioning Stage 9:Aeration
The Conditioning stage involves treatment of the product load within the sterilization cycle, prior to
EO admission, in order to attain a predetermined temperature and relative humidity. This part of the
sterilization cycle is carried out completely under vacuum in the GS Seriessterilizer.
During Aeration, EO desorbs from the product load and devices until predetermined levels of EO
are reached. Aeration in the GS Series sterilizer begins automatically after the sterilization cycle is
complete. Aeration duration is based on the selection made by the Operator, either a specific time or
continuousaeration.
The U.S. Environmental Protection Agency (EPA) requires U.S. healthcare facilities to complete
full aeration within the sterilizer chamber prior to transferring the load. This practice eliminates
the potential for EO exposure that might occur if the load were transferred to a separate aeration
chamber prior to fullaeration.
Stage 5: EOInjection [No Icon] Stage 10: Air AdmissionStage
When the 3M™ Steri-Gas™ EO Gas Cartridge is punctured, EO is vaporized and pulled into the
chamber by the pre-injection chamber vacuumlevel.
Filtered air is admitted into the chamber to allow the chamber pressure to equilibrate with
ambient pressure. An “Opening door…” message will appear on the display screen during the Air
Admissionstage.